Rotary vane pump or motor



Dec. 29, 1959 ERDMANN 2,918,873

ROTARY VANE PUMP OR MOTOR Filed Jan. 31, 1958 2 Sheets-Sheet l N Q l k E N I w h INVENTOR.

M l 190%): XYY'OF/VEFY Filed Jan. 31, 1958 Dec. 29, 1959 H. ERDMANN 2,918,873

ROTARY VANE PUMP OR MOTOR Sheets-Sheet 2 INVENTOR.

array/kins United States Patent ROTARY VANE PUMP OR MOTOR Hans Erdmann, Frankfurt am Main, Germany, assignor to Alfred Teves, Maschinen-und Armatureenfahrik KG, Frankfurt am Main, Germany Application January 31, 1958, Serial No. 712,467 Claims priority, application Germany March 27, 1957 1 Claim. (Cl. 103-42) The invention relates to a rotary vane pump provided with means to avoid the destruction of the housing by the influence of too much pressure created by the hydraulic fluid. It is the object of the invention to relieve the housing of hydraulic pressure completely.

According to the invention, the rotary pump or motor has a suction chamber which is constructed as a belt channel, situated between the cam plate and the housing. The construction of the interior of the housing as a suction chamber possesses the advantage that the oil which is under feed pressure is not admitted to the housing. Thereby, the possibility that the housing may burst is eliminated. This type construction has the further advantage that the admission ways to the inlet ports are of equal length due to the construction of the belt channel so that equal filling of the pockets is assured. In the constructions hitherto known, when dual inlets are used, one inlet slot is served directly from the suction line while the other inlet slot is reached only after the liquid has passed the cam plate and the pockets of the side plates. This longer travel entails a greater throttling of the liquid stream which, in turn, eflects unequal filling of the different cylinder spaces.

A further embodiment of the invention consists in the construction of the housing cover as a pressure relief valve between the pressure chamber and the suction chamber in a manner that a connection is obtained between said pressure and suction chambers when pressure is exerted on the cover greater than the tension of the bolts holding the cover thereby lifting said cover. However, although the two chambers are connected in that manner, the cover continues to seal off the outer area. This is of importance because in daily practice pumps are actuated toward blocked suction lines and also because impact pressures are created in the pressure line, usually from the direction of the working cylinder which cannot be diverted sufficiently fast by the pressure relief valve installed in the system. This often is the case with bulldozers equipped with hydraulically lifted and lowered leveling blades, when the latter are being lowered while the track hits an uneven road and tips on the leveling blade.

An embodiment of the invention is presented in the accompanying drawings and is described below. However, this example is given only by way of illustration, not of limitation, and it is understood that many deviations in the details are possible without departing from the spirit of the invention.

In the drawings:

Fig. 1 is a cross section and Fig. 2 is a longitudinal section through the pump.

In these drawings, 1 is the housing, 2 the housing cover, 3 the driving shaft and 4 the rotor connected with the latter. Between the housing and the cover, suction disc 5, cam plate 6 and pressure plate 7 are installed. Vanes 8 are movable in the rotor slits and are actuated by the curve of the cam plate.

The hydraulic fluid enters housing 1 at point 9 and is discharged into the suction chamber 10 which circularly surrounds the cam plate. The hydraulic fluid is conducted from 10 into the pockets by way of the suction chambers 11 and 12. The construction of the suction chambers according to the invention prevents, as mentioned before, the exertion of pressure upon the housing by the liquid which is under feed pressure, so that possible destruction of the housing is forestalled.

In former pump constructions, it has been proven that narrow, winding channels throttle such supply lines for the supply of the pressure means in a disadvantageous manner. According to the present invention, the pressureless ring channel 10 encloses the cam plate 6 by more than double its own width. Furthermore, the width of suction rooms 11 and 12 are adapted to the width of suction chamber 10.

A gasket 13 is installed between housing cover 2 and housing 1, but the plane surface of the cover is fitted to the pressure plate 7 without a gasket. Another gasket 14 is provided near the drive shaft between the cover and pressure plate 7. The cover is connected to the housing by means of threaded bolts 15. When the feed pressure exceeds the tension of these bolts, the cover lifts olf the plane surface separating pressure chamber and suction chamber far enough for the hydraulic fluid to flow back from the pressure chamber 16 to the suction chamber 10 by way of axial bore holes 18 in the pressure plate or in slit 17 between pressure plate 7 and housing 1. The gasket 13 thereby prevents the escape of the pressure agent from the housing.

What I claim is:

A rotary hydraulic fluid vane pump or motor comprising a housing having an integral closed end and an open end, a housing cover displaceably secured to said open end and forming a pump chamber, a cam plate arranged axially of said housing, said housing further being provided with a very spacious suction chamber communicating directly with the interior of said pump chamber, tension means securing said housing cover to said housing, a shaft rotatable in said housing, a rotor mounted on said shaft and formed with rotor chambers, said pump chamber being formed with very large pockets through which hydraulic fluid enters the rotor chambers, a suction disc interposed between said closed end and said rotor, a pressure plate in said housing between said rotor and said cover, said pressure plate having axial bores communicating with said suction chamber, said pressure plate being circumferentially spaced from the open end of said housing and forming a spaced opening with the inner face of the latter, said pressure plate and said spaced opening being normally closed by the housing cover, whereby when the feed pressure of the hydraulic fluid exceeds the pressure of the tension means, said cover is shifted to allow the fluid to flow from the pressure chamber to the suction chamber by way of said axial bores and said spaced opening for relieving the pressure in said housing. I

References Cited in the file of this patent UNITED STATES PATENTS 776,658 Francisco Dec. 6, 1904 1,927,395 Edwards Sept. 19, 1933 2,312,655 Lauck Mar. 2, 1943 2,405,061 Shaw July 30, 1946 2,434,135 Witchger Jan. 6, 1948 2,649,737 Hoen et a1. Aug. 25, 1953 2,765,745 Sadler et a1. Oct. 9, 1956 FOREIGN PATENTS 80,737 Holland Mar. 15, 1956 

